stumped again

[happy1970GMC]

So I've got good spark from the spark plug wire to the frame, I have rebuilt my quadrajet, #7043208, I have fresh gas and a new filter in the carburetor, the carter electric fuel pump seems to work fine, and the truck runs fine in the driveway--- for 20 minutes. I don't have a choke. There is a well in the intake manifold for a bimetallic spring, and a cable from the bottom of the dash, but it's not hooked to anything. According to Cliff Ruggles's book, this carb had a manual choke, I don't know if it's missing parts or what. I'd really like to be able to drive this truck, any help with what's wrong with it would be greatly appreciated.

[oklalawnboy]

What happens after 20 minutes? Sputter and die? Have you looked down the carb after it dies while moving the throttle to see if it is spraying fuel?

[geezer#99]

No quads ever had a factory manual choke.

[rsavage]

That had a divorced coil spring type choke. You are missing a piece of linkage, a spring type clip, the spring and the little metal cove that goes over it.

[OJ1988]

Someone has converted it to manual choke. you can see the cable in the pics.

Try wiring the choke open.

[happy1970GMC]

Thanks for letting me know about the manual choke thing.

[happy1970GMC]

So do I find the original type of choke, or how do I hook up the manual choke? I wired the choke open and it idled with only a little help from me on the throttle for 30 minutes.After that I had to keep giving it gas. I let it die, then checked to see if gas was going into the carb. It was getting a good stream of gas. Thanks for the help.

[faribran]

tie the flap back, pat the gas, baby it til it warms up.. then drive the doo out of it.

[tubbedII]

Originally Posted by faribran

tie the flap back, pat the gas, baby it til it warms up.. then drive the doo out of it.

That's how I drive my Holley!

[ole dollor]

happy1970gmc: after 30 min. of running the motor is warm enough to run without a choke, a choke is only needed for cold starts...really dont need one in the summer....if you are having to feather it to keep it running than some thing else is wrong, vacuum leak, timing to slow, carb not adjusted right . idle to slow....idle jets are stopped up.....something ....i would do some more looking and see if it helps your problem..

[happy1970GMC]

Thanks guys, I'll go through the list of checks this weekend, then drive the doo out of it!

[Stevo427]

Hook up a vacuum gauge to your engine.. You'll find your problem in minutes

[happy1970GMC]

So I get to buy a new tool? Cool! I'm a machinist and will buy a tool just so I don't have to walk around it! As always, thanks for the help!

[Stevo427]

Yeah just google how to read a vacuum gauge and you'll be able to rule out various problems or solve it. Found out my friend had a bent valve the other day using my guage
Posted via Mobile Device

[happy1970GMC]

Originally Posted by Stevo427

Yeah just google how to read a vacuum gauge and you'll be able to rule out various problems or solve it. Found out my friend had a bent valve the other day using my guage
Posted via Mobile Device

So I got the vacuum gauge. I have about 16" of vacuum, but corrected for my altitude, that's only 11.5". That lasts for about 20 minutes, then drops off and the truck dies. It was near a hundred degrees here, so I wouldn't think it would take 20 minutes to warm up. The needle flickers about 1", but is consistent other than that. How likely is it to have a vacuum leak open up after 20 minutes? I bought a new little propane bottle to look for a leak. Thanks for any help.

[OJ1988]

Is the choke open?
Posted via Mobile Device

[happy1970GMC]

Originally Posted by OJ1988

Is the choke open?
Posted via Mobile Device

Yes, it's wired open.